Salt Marsh Moth Caterpillar
I went up front to the main road 'meadow' to see if there were any more buckeye cats on the agalinis. I had just started looking and found this "big buckeye"! :)
The cat hasn't moved off the agalinis, so I'm thinking it's probably ready to make its cocoon. I brought the cat in to a cage and put a piece of fresh agalinis in with it in case it's still eating. I've never found a salt marsh moth caterpillar on the same host plant twice, they're real generalists. It kept its head down at all times, so I couldn't see its head to see if it has the diagnostic yellow line, but I'm pretty sure this is a salt marsh moth cat.
I think they're very attractive, and the adults are beauties!